The two leading causes of produce spoilage are water loss via evaporation through the produce surface, and oxidation via reaction with oxygen gas that has diffused into the produce. Conventional approaches to preventing spoilage such as refrigeration or special packaging are costly to implement. Refrigeration requires expensive capital equipment, must be actively managed, has constant energy demands while operating, and can cause damage or quality loss to the produce. Special packaging requires expensive equipment, must be actively managed, and consumes packaging materials. Even with refrigeration and special packaging, the handling and transportation of the produce causes surface abrasion or bruising that is aesthetically displeasing to the consumer and serves as points of ingress for bacteria and fungi.
As a natural defense against spoilage, the aerial surfaces of all land plants are covered by a thin, highly cross-linked polyester known as cutin. Depositing an edible coating atop this cutin layer has been shown to reduce post harvest water loss and oxidation while helping resist surface abrasion. However, it is difficult to generate these coatings from non-toxic solvents with optimal diffusion barrier properties, as the films need to be processable (i.e. they must be highly soluble). Thus, conventional application of most edible coatings requires two steps; the deposition of the film, followed by a separate crosslinking step. These multiple processing steps make the use of edible coatings difficult to commercialize and increase the handling requirements of the produce.